1. Field of the Invention
This invention relates to a disc chucking device of an optical disc drive which loads an optical disc using a disc tray, and chucks the loaded optical disc on a disc table using a chucking pulley.
2. Description of Related Art
A sort of optical disc drive which the inventors of the present invention have applied is described with reference to FIGS. 11 to 18. In detail, as shown in FIG. 17, an optical disc 1 is placed horizontally in a pit 3 formed on the upper surface of a disc tray 2, thereafter, when a front panel 2a of the disc tray 2 is pressed lightly in the direction indicated by an arrow a1, a loading switch (not shown in the drawing) is turned on, the disc tray 2 is drawn horizontally from the direction indicated by the arrow a1 namely the loading direction into the optical disc drive through a tray gate 4 by means of a loading mechanism which will described hereinafter as shown in FIG. 18, and as the result, the optical disc 1 is automatically loaded horizontally on a disc table of a spindle motor.
After loading, the optical disc 1 is rotated at high speed by the spindle motor in response to a recording and/or reproducing command signal supplied from a host computer, data in the optical disc 1 is recorded and/or reproduced by an optical pickup. After reproduction of the optical disc 1, the disc tray 2 is unloaded automatically in the direction of the arrow a2 namely the unloading direction to the outside of the optical disc drive through the tray gate 4 in response to an unloading command signal supplied from the host computer as shown in FIG. 17.
Next, as shown in FIGS. 11 to 16, the disc tray 2 consists of synthetic resin, and a slotted hole bottom aperture 8 is formed along a tray center P1 extending from the center of the pit 3 to the rear end 2b side. A pair of right and left guide rails 9 is formed combinedly in parallel to the tray center P1 on the right and left side edges of the disc tray 2. On one end of the bottom surface of the disc tray 2, J-shaped parallel rack 10 and guide groove 11 are formed combinedly. The linear portions 10a and 11a of the rack 10 and the guide groove 11 are formed in parallel to the tray center P1, and on the end of the front panel 2a side, the circular portions 10b and 11b are formed.
Next, a box-shaped chassis formed of synthetic resin is provided in the internal of the optical disc drive 5, and the pair of right and left guide rails 9 of the disc tray 2 is guided by a plurality of tray guides 15 formed combinedly on the inside of the right and left side plates 14a of the chassis 14 and slid in the direction of arrows a1 and a2. A lift frame 16 formed of synthetic resin is attached on the bottom 14b of the chassis 14. Insulator fixing members 17 and 18 are formed combinedly at two positions on the right and left sides of the rear end 16a side of the lift frame 16 and at the center position of the front end 16b of the lift frame 16, namely total three positions, and three insulators 19 and 20, which are dampers consisting of elastic material such as rubber, are fixed to these insulator fixing members 17 and 18.
The right and left insulators 19 fixed to the rear end 16a of the lift frame 16 are fixed on the bottom 14b of the chassis 14 with a fixing screw 21 inserted through the center of these insulators 19, one insulator 20 fixed to the front end 16b of the lift frame 16 is fixed on the end of the lift driving lever 23 with a fixing screw 22 inserted through the center of the insulator 20. The lift driving lever 23 is disposed perpendicularly to the tray center P1 and the base of the lift driving lever 23 is attached on the bottom 14b of the chassis 14 with a pair of horizontal right and left support pins 24 so that the lift driving lever 23 is rotatable in the vertical direction namely in the direction of arrows b1 and b2.
In other words, the lift frame 16 is structured so as to be driven vertically in the direction of arrows c1 and c2 correspondingly to rotational movement in the vertical direction around the pair of right and left insulators 19 of the rear end 16a side by the lift driving lever 23. A shallow groove 25 is formed on the upper surface of the lift frame 16.
The loading mechanism 27 is mounted on one side of the front end 16b side of the lift frame 16 on the bottom 14b of the chassis 14. The loading mechanism 27 is provided with a loading motor 28, a pinion 29 which is rotated in forward-reverse direction by the loading motor 28, a pinion lever 31 which moves a center shaft 29a of the pinion 29 swingingly in the direction of arrows d1 and d2 in the horizontal plane around a vertical rocking lever shaft 30, a cam lever 34 which is driven by the pinion lever 31 with interposition of a pair of partial gears 32 and rotated in the direction of the arrows e1 and e2 in the horizontal plane around a vertical rocking lever shaft 33, a camgroove 35 formed circularly around the rocking lever shaft 33 of the cam lever 34 having a level difference in the vertical direction, and a cam driven pin 36 formed combinedly on one side of the end of the lift driving lever 23 and engaged movably in the cam groove 35. The pinion 29 is engaged in the rack 10 of the disc tray 2, and the center shaft 29a of the pinion 29 is engaged movably in the guide groove 11.
The loading mechanism 27 allows the pinion 29 to move along the J-shaped rack 10 of the disc tray 2 by guiding the center shaft 29a of the pinion 29 along the approximately J-shaped guide groove 11 of the disc tray 2. In detail, when a disc is loaded on the disc tray 2, the pinion 29 which is driven in forward-reverse direction by the loading motor 28 drives the linear portion 10a of the rack 10 linearly toward the front panel 2a side from the rear end 2b side of the disc tray 2 and thereby draws the disc tray 2 in the optical disc drive 5 horizontal in the direction of the arrow a. Continuous forward rotation of the pinion 29 by the loading motor 28 allows the pinion 29 to swing in the direction of the arrow d along the circular portion 10b of the rack 10, when, the pinion lever 31 rotates the cam lever 34 in the direction of the arrow e1 with interposition of the pair of partial gears 32.
The cam driven pin 36 of the lift driving lever 23 is elevated upward namely in the direction of the arrow b1 in the cam groove 35 of the cam lever 34, thereby the lift frame 16 is lifted upward in the direction of the arrow c1 around the pair of right and left insulators 19 using the lift driving lever 23 with interposition of the insulator 20 from the lower position with downward inclination as shown in FIG. 15 to the lifted horizontal upper position as shown in FIG. 16. When the disc tray 2 is unloaded, the reversed loading operation is operated, in detail, the cam lever 34 is rotated in the direction of the arrow e2 while the pinion 29 which is reversibly rotated by the loading motor 28 is swung in the direction of the arrow d2 along the circular portion 10b of the rack 10, the cam driven pin 36 is driven downward in the direction of the arrow b2 namely downward along the cam groove 35, and the lift driving lever 23 drives the lift frame 1b downward in the direction of the arrow c2 around the pair of right and left insulators 19 with interposition of the insulator 20 from the upper position shown in FIG. 16 to the lower position shown in FIG. 15. In continuous reverse rotation of the pinion 29 driven by the loading motor 28, the pinion 29 drives linearly the linear portion 10a of the rack 10 from the front panel 2a side to the rear end 2b of the disc tray 2, and the disc tray 2 is pressed out in the direction of the arrow a2 to the outside of the optical disc drive 5.
In the shallow groove 25 of the lift frame 16, a spindle motor 39 is fixed vertically on the mounting member 38 formed at the position deviated to the front end 16b, a disc table 40 consisting of magnetic metal material such as stainless steel is fixed on the top end of the motor shaft 39a. A conical trapezoid centering guide 40a to be engaged into the center hole 1a of the optical disc 1 is formed combinedly on the upper center of the disc table. An optical pickup 41 is fixed horizontally on the rear side from the spindle motor 39 in the shallow groove 25 of the lift frame 16. The optical pickup 41 has a carriage 44 on which an objective lens 42 and light reflection type skew sensor 43 are fixed upward vertically, and an optical block 45 for transmitting a laser beam to the objective lens is fixed combinedly on the side of the carriage 44.
A carriage moving mechanism 47 for moving linearly the carriage 44 in the direction of the arrows a1 and a2 along a pair of right and left guide shafts 46 is fixed on the lift frame 16, and the carriage moving mechanism 47 is provided with a pinion 50 which is rotationally driven forward-reversibly by a carriage driving motor 48 with interposition of a gear train 49 and a rack 51 fixed on one side of the carriage 44 which rack 51 is driven linearly by the pinion 50. The spindle motor 39 and the objective lens 42 are disposed on the tray center P1, and the mechanism is structured so that the objective lens is moved in the direction of the arrows a1 and a2 along the tray center P1.
A disc chucking device 61 for chucking an optical disc 1 on the disc table 40 has a structure described herein under.
In detail, a pulley support member 62 formed of synthetic resin is spanned between the top ends of the right and left side plates 14a of the chassis 14 across the upper space of the disc tray 2, and a chucking pulley 63 formed of synthetic resin in the form of disc is held horizontally in a circular hole 64 formed at the position just above the disc table 40 and at the center position of the pulley support member 62 movably in the vertical and horizontal direction within a certain range. A horizontal pillow block 62a for supporting the horizontal flange 63a formed combinedly to the periphery of the upper edge of the chucking pulley 63 thereon is formed combinedly to the periphery of the circular hole 64 of the pulley support member 62. A disc magnet 65 is embedded at the center of the chucking pulley 63. A top cover 26 consisting of magnetic material such as metal plate is attached across the pulley support member 62 in the upper space of the chassis 14.
Therefore, when a disc is loaded, the chucking pulley 63 is lowered downward to the space under the pulley support member 62 with the dead load as shown in FIG. 15, the flange 63a of the chucking pulley 63 is hung in contact with the top of the pulley pillow block 62a of the pulley support member 62, the optical disc 1 is placed horizontally in the pit 3 of the disc tray 2, and the optical disc 1 is loaded horizontally in the direction of the arrow a1 into the optical disc drive 5 by the disc tray 2. After loading, as shown in FIG. 1, when the lift frame 16 is lifted in the direction of the arrow c1 up to the upper horizontal position, the disc table 40 is inserted upward from the bottom aperture 8 of the disc tray 2, and a center ring guide 40a of the disc table 40 is engaged upward into the center hole 1a of the optical disc 1. The optical disc 1 is lifted upward in the direction of the arrow b1 in the pit 3 of the disc tray 2, simultaneously the chucking pulley 63 is lifted upward in the direction of the arrow b1 together with the optical disc 1, and the flange 63a is lifted upward to the space above the pulley pillow block 62a of the pulley support member 62, when, the chunking pulley 63 chucks the optical disc 1 horizontal on the disc table 40 from the direction of the arrow b2 by means of magnetic attraction of the magnet 65 of the chucking pulley 63 to the disc table 40.
The spindle motor 39 rotates the optical disc 1 at high speed in response to a recording and/or reproducing command signal supplied from the host computer, the carriage 44 of the optical pickup 41 is moved in the direction of the arrows a1 and a2 by the carriage moving mechanism 47, and the objective lens 42 is moved in the direction of the arrows a1 and a2 along the tray center P1. A laser beam emitted from the optical block 45 irradiated onto the bottom face of the optical disc 1 through the objective lens 42, and the reflective beam is received by the optical block 45 through the objective lens 42, thereby the data of the optical disc 1 is recorded and/or reproduced.
The pinion 50 which is driven forward-reversibly by the carriage driving motor 48 with interposition of the gear train 49 drives linearly the rack 51, thereby the carriage moving mechanism 47 moves the carriage 44 in the direction of the arrows a1 and a2 along the pair of right and left guide shafts 46. The lift frame 16 is lowered in the direction of the arrow c2up to the lower position in response to an unloading command signal supplied from the host computer as shown in FIG. 15, and the disc table 40 is isolated downward from the optical disc 1 and the chucking pulley 63, thereafter the optical disc 1 is placed horizontally in the pit 3 of the disc tray 2, and the optical disc 1 is unloaded horizontally in the direction of the arrow a2 to the outside of the optical disc drive 5 by the disc tray 2. When, the flange 63a of the chucking pulley 63 is brought into a contact with the pulley pillow block 62a of the pulley support member 62 in the direction of the arrow b2 and brought to a stop when the disc table 40 is lowered in the direction of the arrow c2, as the result, the disc table 40 is separated forcedly from the chucking pulley 63 against magnetic attraction force of the magnet 65.
In the exemplary chucking device 61 of the previously applied invention, as shown in FIG. 15, when an optical disc 1 is loaded or unloaded horizontally in the direction of the arrows a1 and a2 by the disc tray 2, the chucking pulley 63 is lowered to the space beneath the pulley support member 62 with the dead load and the flange 63a of the chucking pulley 63 is hung in a contact with the top of the pulley pillow block 62a of the pulley support member 62, therefore when an optical disc 1 is loaded or unloaded, a clearance L should be secured between the bottom surface of the hung chucking pulley 63 and the top surface of the optical disc 1 placed horizontally in the pit 3 of the disc tray 2 so that the optical disc 1 does not interfere with the chucking pulley 63. Therefore, in the example of an optical disc drive of the previously applied invention, when an optical disc 1 is loaded or unloaded, in order to secure further a clearance L between the chucking pulley 63 and the optical disc 1 in the state that the chucking pulley 63 is lowered from the pulley support member 62 by the clearance L2, a large space namely L1+L2 is necessary between the pulley support member 62 and the top surface of the optical disc 1, as the result, the space causes the large total thickness T of the optical disc drive 5, and the large thickness is a problem.
In the exemplary disc chucking device 61 of the previously applied invention, the circular hole 64 is formed at the center of the pulley support member 62 provided horizontally beneath the top cover 26 across over the chassis 14, and the chucking pulley 63 is pressed in the circular hole movably in the vertical and horizontal direction within a certain range, the pulley support member 62 supports the periphery of the chucking pulley 63.
On the other hand, two types of use of optical disc drive 5 of this sort have been practically employed. One is the horizontal type in which the apparatus is placed horizontally on a desk for using and the other is the vertical type in which the apparatus is placed vertically on a desk for using. In particular, in the case of the vertical use, when an optical disc 1 is loaded or unloaded by the disc tray 2, the optical disc 1 moved toward the chucking pulley 63 from the disc tray 2 (shifted horizontally), and the top surface of the optical disc 1 (the side facing to the chucking pulley) can happen to be in contact with the chucking pulley 63 and the pulley support member 62. If the top surface of the optical disc 1 contacts with the pulley support member 62 fixed to the chassis 14, a scratch is caused on the top surface of the optical disc 1 due to a large contact resistance. Particularly in the case of an optical disc 1 for DVD (digital video disc) having information on both top and bottom surfaces, if scratching is caused on the top information recorded surface due to contact with the pulley support member 62, then the information can be impossible to be recorded and/or reproduced, this is a serious problem.
The present invention has been accomplished in order to solve the above-mentioned problem, it is the object of the present invention to provide a disc chucking device of an optical disc drive for eliminating occurrence of scratching due to a contact of the top surface of an optical disc with a pulley support member even if the optical disc is lifted part from a disc tray when the optical disc is loaded or unloaded in the case that the optical disc drive is in vertical use.
To achieve the above-mentioned object, the disc chucking device of an optical disc drive of the present invention is provided with a first magnetic attraction means for drawing down a chucking pulley to the disc table side when the disc table is lifted from the lower position to the upper position after an optical disc is loaded, and a second magnetic attraction means for drawing up the chucking pulley from the pulley support member when the disc table is drawn down from the upper position to the lower position to unload the optical disc, and further the pulley support member is structured with a centering guide which supports the center of the chucking pulley.
Because the disc chucking device of an optical disc drive of the present invention having the structured described herein above is capable of keeping the chucking pulley above the pulley support member using the second magnetic attraction means in unloading state of an optical disc, the optical disc will not receive interference from the chucking pulley when the disc tray loads the optical disc. Because the chucking pulley can be drawn down strongly toward the pulley support member by the first magnetic attraction means when the disc table is lifted from the lower position to the upper position after loading of the optical disc, the optical disc can be chucked strongly on the disc table by the chucking pulley. On the other hand, because the chucking pulley can be kept above the pulley support member when the optical disc is unloaded, the clearance to be secured in unloading between the chucking pulley and the optical disc is reduced to a clearance L8 which is sufficiently smaller than L1+L2 in the previously applied invention. Because the pulley support member is structured with the centering guide which supports the center of the chucking pulley, the top surface of the optical disc is prevented from being scratched due to contact with the centering guide even if the optical disc is lifted far apart from the disc tray when the optical disc is loaded and unloaded in the case that the optical disc drive is placed vertically for use.